We must put the brakes on glaciers to stop the seas rising

The public may balk at geoengineering, but we've got to think boldly if we're going to protect our coasts, says glaciologist Slawek Tulaczyk

By Anil Ananthaswamy

“We haven’t yet considered putting the brakes on glaciers. But we should”

(Image: Timothy Archibald)

You have been studying the Whillans ice stream in West Antarctica. Tell us about it.It’s one of the largest ice streams draining the West Antarctic ice sheet, hundreds of kilometres long and about 100 kilometres wide. It used to discharge as much water as the Missouri river in the US.

What is it that you find intriguing about that ice stream?Whillans is behaving oddly. It is slowing down. Because of internal ice-sheet dynamics, it has lost about 50 per cent of its velocity compared with the 1970s. It’s switching from negative mass balance – where the outflow of ice exceeds the accumulation of snow – to positive mass balance. A positive mass balance can help contain sea level rise.

Another large ice stream next to it, Kamb, stopped moving about 150 years ago. If we can understand the mechanical processes at the base of the ice that are making these huge slabs slow down, then maybe one day we could regulate the flow of ice and slow the rate of sea level rise.

Are you talking about geoengineering ice streams to control sea level rise?Yes. When we talk about geoengineering we usually mean bringing down levels of carbon dioxide or controlling Earth’s reflectivity to sunlight. We haven’t yet considered putting the brakes on ice streams and glaciers, but we should be considering this possibility. Last month in Nature, new results corroborated previous evidence showing that the loss of mass from polar ice sheets accelerated in the last decade (DOI&colon; 10.1038/nclimate2635).

We haven’t yet considered putting the brakes ...

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